Chapter 16 - Endocrine System Flashcards
1
Q
Characteristics of exocrine glands
A
- Non-hormonal (sweat, saliva)
2. Have ducts to carry secretion to membrane surface
2
Q
Characteristics of endocrine glands
A
- Hormonal
2. No ducts
3
Q
Name the endocrine glands
A
- Pituitary gland
- Thyroid gland
- Parathyroid gland
- Adrenal gland
- Pineal gland
4
Q
The hypothalamus is a ____ organ.
A
Neuroendocrine
5
Q
Organs that have both endocrine and exocrine functions
A
- Pancreas
- Gonads
- Placenta
6
Q
Other tissues and organs that produce hormones:
A
- Adipose cells
- Thymus
- Cells in walls of small intestine
- Stomach
- Kidneys
- Heart
7
Q
Different chemical messengers
A
- Hormones
- Autocrines
- Paracrines
8
Q
long-distance chemical signals; travel in blood or lymph
A
Hormones
9
Q
Chemicals that exert effects on same cells that secrete them
A
Autocrines
10
Q
Locally acting chemicals that affect cells other than those that secrete them
A
Paracrines
11
Q
Two main classes of hormones
A
- Amino acid-based
2. Steroids
12
Q
Peptides and proteins
A
Amino acid-based hormones
13
Q
Synthesised from cholesterol; gonadal and adrenocortical hormones
A
Steroids
14
Q
Hormone action on target cells may be to
A
- Alter plasma membrane permeability and/or membrane potential by opening or closing ion channels
- Stimulate synthesis of enzymes or other proteins
- Activate or deactivate enzymes
- Induce secretory activity
- Stimulate mitosis
15
Q
All amino acid-based hormones are ____ except ____.
A
Water-soluble; thyroid hormone
16
Q
How do water-soluble hormones act on receptors?
A
- Act on plasma membrane receptors
- Act via G protein second messengers
- Can not enter cell
17
Q
Steroid and thyroid hormones are ___-soluble.
A
Lipid
18
Q
How do lipid-soluble hormones act on receptors?
A
- Act on intracellular receptors that directly activate genes
- Can enter cell
19
Q
What are the signaling mechanisms?
A
- cAMP signaling mechanism
2. PIP2-calcium signaling mechanism
20
Q
Steps of cyclic AMP signaling:
A
- Hormone (1st messenger) binds to receptor
- Receptor activates G protein
- G protein activates adenylate cyclase
- Adenylate cyclase converts ATP to cAMP (2nd messenger)
- cAMP activates protein kinases that phosphorylate proteins
21
Q
Activated kinases:
A
phosphorylate various proteins, activating some and inactivating others
22
Q
cAMP is rapidly degraded by the enzyme _____.
A
phosphodiesterase
23
Q
______ have huge amplification effect during cAMP signaling.
A
Intracellular enzymatic cascades
24
Q
PIP2-calcium signaling mechanism involves ____.
A
phospholipase C
25
G protein and membrane-bound effector
phospholipase C
26
Phospholipase C splits PIP2 into _____.
2 second messengers
27
What are the two second messengers?
1. diacylglycerol (DAG)
| 2. inositol triphosphate (IP3)
28
What is the function of diacylglycerol?
activates protein kinase
29
What is the function of inositol triphosphate?
causes Ca2+ release
30
Calcium ions act as ____.
Second messenger
31
Ca2+ alters ______ or binds to _____.
enzyme activity and channels; calmodulin
32
Regulatory protein
Calmodulin
33
When calcium binds to calmodulin, what happens?
The calmodulin activates enzymes that amplify cellular response.
34
_____ is second messenger for some hormones.
Cyclic guanosine monophosphate (cGMP)
35
Steroid hormones and thyroid hormone diffuse into ____ and bind with ____.
target cells; intracellular receptors
36
____ enters nucleus; binds to specific region of DNA.
Receptor-hormone complex
37
After the receptor-hormone complex binds to a specific region of DNA:
It prompts DNA transcription to produce mRNA
38
mRNA directs:
protein synthesis
39
mRNA promotes:
1. Metabolic activities
2. Synthesis of structural proteins
3. Synthesis of proteins for export from the cell
40
Target cell activation depends on three factors:
1. Blood levels of hormone
2. Relative number of receptors on or in target cell
3. Affinity of binding
41
target cells form more receptors in response to low hormone levels
Up-regulation
42
target cells lose receptors in response to high hormone levels
Down-regulation
43
Endocrine gland stimulated to synthesise and release hormones in response to:
1. Humoral stimuli
2. Neural stimuli
3. Hormonal stimuli
44
Example of humoral stimuli:
Ca2+ levels in the blood
45
Example of neural stimuli:
Sympathetic nervous system fibers stimulate adrenal medulla to secrete catecholamines
46
Example of hormonal stimuli:
Hormones stimulate other endocrine organs to release their hormones. Ex. Hypothalamic --> Anterior Pituitary --> target
Organ feedback loop
47
Steroid and thyroid hormone in the blood are attached to:
plasma proteins
48
Hormones are removed from the blood by:
1. Degrading enzymes
2. Kidneys
3. Liver
4. Half-life
49
time required for hormone's blood level to decrease by half
Half-life
50
Different interactions of hormones at target cells:
1. Permissiveness
2. Synergism
3. Antagonism
51
one hormone can not exert its effects without another hormone being present
Permissiveness
52
More than one hormone produces same effects on target cell which leads to amplification
Synergism
53
One or more hormones opposes action of another hormone
Antagonism
54
Pituitary gland is also called
Hypophysis
55
Anterior pituitary is also called
Adenohypophysis
56
Which pituitary has a neural connection to the hypothalamus?
Posterior
57
The neural connection is called
Hypothalamic-hypophyseal tract
58
Nuclei of hypothalamus synthesise
1. Oxytocin
| 2. Antidiuretic hormone (ADH)
59
Neurohormones are transported to and stored in
posterior pituitary
60
____ carries releasing and inhibiting hormones to anterior pituitary to regulate hormone secretion.
Anterior lobe
61
Characteristics of oxytocin:
1. Strong stimulant of uterine contraction
2. Released during childbirth
3. Hormonal trigger for milk ejection
4. Acts as neurotransmitter in the brain
62
Characteristics of ADH (Vasopressin):
1. Inhibits or prevents urine formation
2. Regulates water balance
3. Targets kidney tubules which leads to reabsorbing more water
4. Release also triggered by pain, low blood pressure, and drugs
5. Inhibited by alcohol, diuretics
6. High concentrations lead to vasoconstriction
63
What is diabetes insipidus?
ADH deficiency due to hypothalamus or posterior pituitary damage
64
Characteristics of Syndrome of inappropriate ADH secretion ( SIADH)
1. Retention of fluid, headache, disorientation
| 2. Fluid restriction; blood sodium level monitoring
65
What are the anterior pituitary hormones?
1. Growth hormone (GH)
2. Thyroid-stimulating hormone (TSH)
3. Adrenocorticotropic hormone (ACTH)
4. Follicle-stimulating hormone (FSH)
5. Luteinising hormone (LH)
6. Prolactin (PRL)
66
All anterior pituitary hormones are ___.
proteins
67
All anterior pituitary hormones except GH activate:
cAMP second-messenger systems at their targets
68
Which anterior pituitary hormones are tropic hormones?
1. TSH
2. ACTH
3. FSH
4. LH
69
regulate secretory action of other endocrine glands
tropic hormones
70
Characteristics of growth hormone:
1. Direct actions on metabolism
2. Indirect actions on growth
3. Mediates growth via IGFs
71
Growth-Promoting proteins
Insulin-like growth factors (IGF)
72
IGFs stimulate:
1. Uptake of nutrients which leads to DNA and proteins
2. Formation of collagen and deposition of bone matrix
3. Bone and skeletal muscle
73
GH release chiefly regulated by ____.
hypothalamic hormones
74
Stimulates release of growth hormone
Growth hormone-releasing hormone (GHRH)
75
Inhibits release of growth hormone
Growth hormone-inhibiting hormone (GHIH) (somatostatin)
76
hunger hormone
Ghrelin
77
Stimulates release of growth hormone 2
Ghrelin
78
What are the homeostatic imbalances of Growth Hormone?
1. hypersecretion
| 2. hyposecretion
79
Hypersecretion in children results in ____.
gigantism
80
Hypersecretion in adults results in ____.
acromegaly
81
Hyposecretion in children results in ____.
pituitary dwarfism
82
Thyroid-stimulating Hormone is also called:
thyrotropin
83
TSH is produced by:
thyrotropic cells of anterior pituitary
84
TSH stimulates:
normal development and secretory activity of thyroid
85
TSH release is triggered by:
thyrotropin-releasing hormone from hypothalamus
86
TSH is inhibited by:
rising blood levels of thyroid hormones that act on pituitary and hypothalamus
87
Adrenocorticotropic hormone is also called:
corticotropin
88
Adrenocorticotropic hormone is secreted by:
corticotropic cells of anterior pituitary
89
Adrenocorticotropic hormone stimulates ______ to release ____.
adrenal cortex; corticosteroids
90
Adrenocorticotropic hormone is involved in regulation of:
ACTH release
91
Adrenocorticotropic hormone regulation of ACTH is triggered by ______ in daily rhythm.
corticotropin-releasing hormone (CRH)
92
How is the release of CRH altered?
By internal and external factors such as fever, hypoglycemia, or stressors
93
The two gonadotropins are:
1. Follicle-stimulating hormone (FSH)
| 2. Luteinising hormone (LH)
94
Gonadotropins are secreted by:
gonadotrophs of anterior pituitary
95
FSH stimulates:
gamete (egg or sperm) production
96
LH promotes production of ____.
gonadal hormones
97
Gonadotropin release is triggered by ____ during and after puberty.
gonadotropin-releasing hormone (GnRH)
98
Gonadotropin release is suppressed by ____.
gonadal hormones (feedback)
99
Prolactin is secreted by:
prolactin cells of anterior pituitary
100
Prolactin stimulates:
milk production
101
Prolactin is regulated by:
prolactin-inibiting hormone (PIH) (dopamine)
102
What stimulates prolactin release?
suckling
103
Hypersecretion of prolactin causes:
1. inappropriate lactation
2. lack of menses
3. infertility in females
4. impotence in males
104
The Thyroid Gland has two lateral lobes connected by ____.
isthmus
105
The Thyroid Gland is composed of follicles that produce:
the glycoprotein [thyroglobulin]
106
thyroglobulin and iodine compose:
colloid
107
____ fills lumen of follicles
colloid
108
precursor of thyroid hormone
colloid
109
Parafollicular cells produce the hormone ___.
calcitonin
110
Thyroid hormone has two releated compounds:
1. T4 (thyroxine)
| 2. T3 (triiodothyronine)
111
major metabolic hormone
thyroid hormone
112
Thyroid hormone increases:
metabolic rate and heat production (calorigenic effect)
113
Thyroid hormone regulates:
1. tissue growth
2. development of skeletal and nervous systems
3. reproductive capabilities
114
TH maintains:
blood pressure
115
Synthesis of Thyroid Hormone: 1. Thyroid hormone is stored ____ on the thyroid gland.
extracellularly
116
Synthesis of Thyroid Hormone: 2. Outside of the cell, ____ is synthesised and discharged into ____.
thyroglobulin; follicle lumen
117
Synthesis of Thyroid Hormone: 3. ____ are actively taken into the cell and released into lumen.
Iodides (I-)
118
Synthesis of Thyroid Hormone: 4. After release into lumen, iodide is ____ to ___.
oxidised; iodine (I2)
119
Synthesis of Thyroid Hormone: 5. Iodine attaches to ____, mediated by ____.
tyrosine; peroxidase enzymes
120
Synthesis of Thyroid Hormone: 6. Iodinated tyrosines link together to form ___.
T3 and T4
121
Synthesis of Thyroid Hormone: 7. Colloid is endocytosed and combined with ___.
lysosome
122
Synthesis of Thyroid Hormone: 8. T3 and T4 are cleaved and:
diffuse into the bloodstream
123
T3 and T4 are transported by ______.
thyroxine-binding globulins (TBGs)
124
Peripheral tissues convert:
T4 to T3
125
Rising TH levels provide _____ on release of ____.
negative feedback inhibition; TSH
126
______ can overcome negative feedback during pregnancy or exposure to cold.
hypothalamic thyrotropin-releasing hormone (TRH)
127
Hyposecretion of TH in adults leads to ____.
myxedema
128
Hyposecretion of TH in adults if due to lack of iodine can lead to ___.
goiter
129
Hyposecretion of TH in infants leads to ____.
cretinism
130
Hypersecretion of TH hormones leads to ___.
Graves' disease
131
Calcitonin is produced by ____.
parafollicular cells
132
Calcitonin is an antagonist to ___.
parathyroid hormone (PTH)
133
At higher than normal doses, calcitonin inhibits:
1. osteoclast activity
| 2. release of Ca2+ from bone matrix
134
At higher than normal doses, calcitonin stimulates:
1. Ca2+ uptake
| 2. Ca2+ incorporation into bone matrix
135
most important hormine in Ca2+ homeostasis
parathyroid hormone (PTH)
136
PTH stimulates:
osteoclasts to digest bone matrix and release Ca2+ to blood
137
PTH enhances:
reabsorption of Ca2+ and secretion of phosphate by kidneys
138
PTH promotes activation of _____.
vitamin D (by kidneys)
139
PTH increases absorption of
Ca2+ by intestinal mucosa
140
PTH has which type of feedback control?
negative; rising Ca2+ in blood inhibits PTH release
141
Homeostatic imbalance of PTH due to tumour.
hyperparathyroidism
142
What are the characteristics of hyperparathyroidism?
1. bones soften and deform
| 2. Elevated Ca2+ depresses the nervous system and contributes to formation of kidney stones
143
Hypoparathyroidism follows:
gland trauma or gland removal or dietary magnesium deficiency
144
Hypoparathyroidism results in:
1. tetany
2. respiratory paralysis
3. death
145
Adrenal gland is also known as ___.
suprarenal
146
nervous tissue; part of sympathetic nervous system
adrenal medulla
147
three layers of glandular tissue that synthesise and secrete corticosteroids
adrenal cortex
148
What are the three layers of the adrenal cortex?
1. Zona glomerulosa
2. Zona fasciculata
3. Zona reticularis
149
Zona glomerulosa produces ____.
mineralocorticoids
150
Zona fasciculata produces ____.
glucocorticoids
151
Zona reticularis produces ____.
gonadocorticoids
152
Mineralocorticoids regulate _____ in ECF.
electrolytes (primarily Na+ and K+)
153
____ is the most potent mineralocorticoid.
aldosterone
154
Aldosterone stimulates:
1. Na+ reabsorption and water retention by kidneys
| 2. Elimination of K+
155
Aldosterone release is triggered by:
1. decreasing blood volume and blood pressure
| 2. rising blood levels of K+
156
Hypersecretion due to adrenal tumours
aldosteronism
157
Keep blood glucose levels relatively constant
glucocorticoids
158
Glucocorticoids maintain blood pressure by:
increasing action in vasoconstrictors
159
The different glucocorticoids are:
1. cortisol
2. Cortisone
3. corticosterone
160
What is another name for cortisol?
hydrocortisone
161
Cortisol is released in response to:
1. ACTH
2. Patterns of eating and activity
3. Stress
162
The prime metabolic effect of cortisol is ____.
gluconeogenesis
163
formation of glucose from fats and proteins
gluconeogenesis
164
Cortisol saves glucose for:
the brain
165
Cortisol promotes rises in:
1. blood glucose
2. fatty acids
3. amino acids
166
Cortisol enhances ____.
vasoconstriction
167
Hypersecretion of glucocorticoids is:
Cushing's syndrome/disease
168
What happens with hypersecretion of glucocorticoids?
1. depresses cartilage and bone formation
2. inhibits inflammation
3. depresses immune system
4. disrupts cardiovascular, neural, and gastrointestinal function
169
Hyposecretion of glucocorticoids is:
Addison's disease
170
Addison's disease also involves deficits in ___.
mineralocorticoids
171
Characteristics of Addison's disease:
1. decrease in glucose and Na+ levels
2. weight loss
3. severe dehydration
4. hypotension
172
Hypersecretion of gonadocorticoids causes:
Adrenogenital syndrome (masculinisation)
173
Medullary chromaffin cells in the adrenal medulla synthesise ____ and ____.
1. epinephrine (80%)
| 2. norepinephrine (20%)
174
Epinephrine stimulates:
1. metabolic activities
2. bronchial dilation
3. blood flow of skeletal muscles and the heart
175
Norepinephrine stimulates:
1. peripheral vasoconstriction
| 2. blood pressure
176
Hypersecretion of medullary chromaffin cells leads to:
1. hyperglycemia
2. increased metabolic rate
3. rapid heartbeat and palpitations
4. hypertension
5. intense nervousness
6. sweating
177
Hyposecretion of medullary chromaffin:
not problematic; adrenal catecholamines not essential to life
178
Where is the pineal gland located?
hanging from the roof of the third ventricle
179
Pinealocytes secrete:
melatonin
180
Melatonin is derived from:
serotonin
181
Melatonin may affect:
1. timing of puberty
2. day/night cycles
3. Body temperature, sleep, appetite
4. production of antioxidants and detoxification molecules
182
The exocrine cells found in the pancreas:
acinar cells
183
Acinar cells produce:
enzyme-rich juice for digestion
184
____ in the pancreas contain endocrine cells.
Pancreatic islets (islets of Langerhans)
185
Alpha cells in islets of Langerhans produce ___.
glucagon
186
Beta cells in islets of Langerhans produce ____.
insulin
187
Glucagon is a ____ hormone.
hyperglycemic
188
Insulin is a ____ hormone.
hypoglycemic
189
Glucagon's major target is:
the liver
190
Glucagon causes:
increased blood glucose levels
191
The effects of glucagon are:
1. glycogenolysis
2. gluconeogenesis
3. release of glucose to blood
192
breakdown of glycogen to glucose
glycogenolysis
193
synthesis of glucose from lactic acid and noncarbohydrates
gluconeogenesis
194
Insulin lowers ____.
blood glucose levels
195
Insulin enhances:
membrane transport of glucose into fat and muscle cells
196
Insulin inhibits:
glycogenolysis and gluconeogenesis
197
Insulin activates ____ on cells.
tyrosine kinase enzyme receptor
198
Insulin activation cascade leads to:
increased glucose uptake
199
Insulin activation on cells triggers enzymes to:
1. Catalyse oxidation of glucose for ATP production
2. Polymerise glucose to form glycogen
3. Convert glucose to fat
200
Factors that influence insulin release:
1. Elevated blood glucose levels
2. Rising blood levels of amino acids and fatty acids
3. Release of acetylcholine by parasympathetic nerve fibres
4. hormones
5. somatostatin
201
What are the hormones that influence insulin release?
1. Glucagon
2. Epinephrine
3. Growth Hormone
4. Thyroxine
5. Glucocorticoids
202
Type 1 diabetes is caused by:
hyposecretion of insulin
203
Type 2 diabetes is caused by:
hypoactivity of insulin
204
glucose spilled into urine
glycosuria
205
fats used for cellular fuel in diabetes mellitus leads to ____.
lipidemia
206
If lipidemia is severe, it leads to ____ from fatty acid metabolism, which leads to ___ and ___.
ketones (ketone bodies); ketonuria; ketoacidosis
207
Untreated ketoacidosis leads to:
1. hyperpnea
2. disrupted heart activity and O2 transport
3. depression of nervous system
4. coma and death
208
The three signs of Diabetes Mellitus are:
1. Polyuria
2. Polydipsia
3. Polyphagia
209
huge urine output
polyuria
210
excessive thirst
polydipsia
211
excessive hunger and food consumption
polyphagia
212
Excessive insulin secretion
hyperinsulism
213
Hyperinsulism causes ____.
hypoglycemia
214
Hypoglycemia is characterised by:
1. low blood glucose levels
| 2. Anxiety, disorientation
215
Hyperinsulism is treated by:
sugar ingestion
216
Ovaries produce:
1. estrogens
| 2. progesterone
217
Placenta secretes:
1. estrogens
2. progesterone
3. human chorionic gonadotropin (hCG)
218
Testes produce ____.
testosterone
219
Other hormone-producing structures are:
1. adipose tissue
2. enteroendocrine cells of gastrointestinal tract
3. heart
4. kidneys
5. skeleton
6. skin
7. thymus
220
Adipose tissue produces which hormones?
1. Leptin
2. Resistin
3. Adiponectin
221
appetite control; stimulates increased energy expenditure
leptin
222
insulin antagonist
resistin
223
enhances sensitivity to insulin
adiponectin
224
What hormones are produced by enteroendocrine cells of the gastrointestinal tract?
1. Gastrin
2. Secretin
3. Cholecystokinin
4. Serotonin
225
stimulates release of HCl
gastrin
226
stimulates liver and pancreas
secretin
227
stimulates pancreas, gallbladder, and hepatopancreatic sphincter
cholecystokinin
228
acts as paracrine
serotonin
229
What hormone is released by the heart?
Atrial natriuretic peptide (ANP)
230
decreases blood Na+ concentration, therefore blood pressure and blood volume
atrial natriuretic peptide (ANP)
231
What hormones do the kidneys release?
1. Erythropoietin
| 2. Renin
232
signals production of red blood cells
erythropoietin
233
initiates the renin-angiotensin-aldosterone mechanism
renin
234
What hormone does the osteoblasts in the skeleton release?
osteocalcin
235
osteocalcin is activated by ___.
insulin
236
What hormone is secreted by the skin?
cholecalciferol
237
Cholecalciferol is the precursor for:
vitamin D
238
What hormones does the thymus release?
1. Thymulin
2. Thymopoietins
3. Thymosins
classified as hormones; act as paracrines
